1. Field of Invention
The present invention relates generally to computer-aided design/computer-aided manufacturing (CAD/CAM), multimedia, and any other system that supports substantially concurrent viewing and manipulation of electronically captured or generated images, graphics, or text by multiple users and, more particularly, to a graphical consistency verification system for real-time on-the-fly 3-D graphical consistency among multiple applications at different workstations.
2. Discussion of Related Art
Industries that manufacture motor vehicles, airplanes and other complex mechanical equipment require designers and engineers to work concurrently on the same large complex design. The ability to work concurrently on the same design allows multiple users to collaborate on design changes in real-time, thereby reducing overall design time and improving the quality of the final product design.
Computer systems allow designers and engineers to electronically generate and manipulate multidimensional design graphics. The computer software that electronically displays and manipulates graphics displayed on a computer screen is referred to generally as an application program or application. For more than one user to view or work on the same electronically generated graphics at the same time, the application must be shared with each user workstation site. The shared application should provide consistent views or windows of the same image in real-time at each user workstation.
Existing shared applications are based on two general architectures. First, a centralized architecture contains only one instance of the shared application. Inputs to the application are sent to a single execution site. The output of the application at the execution site is then sent to each user workstation display. The centralized architecture provides identical views by transmitting the same protocol to each user display. Second, a replicated architecture executes a copy of each shared application locally at each user workstation. User inputs and outputs to and from the shared application remain localized on the user workstation.
View consistency problems typically do not occur in centralized architectures since only one copy of the application is executed. However, centralized architectures must transfer all input and output (I/O) data between each user workstation and the shared application at the execution site. The I/O data increases network traffic between user workstations. Because networks have limited bandwidths, only a limited number of users can use a centralized shared application architecture concurrently.
Replicated architectures significantly reduce network traffic and have faster response times since I/O data remains localized at the user workstation. However, replicated architectures have difficulty maintaining an on-the-fly image with automatic image checking, among multiple copies of a displayed image at separate workstations. Workstations in a network need the ability to share and communicate contents of an image in multiple applications independent of available network bandwidth.
Accordingly, a need remains for improving real-time on-the-fly graphical images with automatic checking to ensure consistency in replicated architectures while improving response time and reducing data flow on the network.